This invention relates to a coupling.
One practical realisation of this invention is envisaged as residing in an ostomy coupling. The term "ostomy" is intended to include colostomy, ileostomy, urostomy and other surgical diversion procedures.
Ostomy couplings are used to connect and disconnect a bag for receiving a stomal discharge to and from a medical grade adhesive pad which is applied to the peristomal area of the skin of the wearer. Many designs of ostomy coupling are known. One which has enjoyed considerable world-wide commercial success is described and claimed in U.K. Patent No. 1,571,657.
An ostomy coupling in which locking and unlocking is achieved by deforming a ring is disclosed in our U.K. Patent Application No. 9409037.0, filed 6 May 1994.
An ostomy appliance in which a V-section ring holds coupling members together is disclosed in U.S. Pat. Nos. 5,322,522 and 5,322,523.
In PCT Application WO91/01119, published 1991 and corresponding to European Patent 482 104B, there is disclosed a locking ring for an ostomy coupling. An ostomy coupling which embodies such a ring is shown in European Patent 572 378B. Features of this design are that inwardly sprung tongues on the ring peripherally surround the joined coupling parts and that a press-button engagement device as well as a hook and detent engagement device are included, apparently in a quest for secure rotation of the locking ring on the coupling parts. It appears inevitable that quite intricate manipulation of this design of coupling is needed when applying or removing the bag.
It has been proposed by Kubo, in Japanese Utility Model No. 62-11610, published February 1985, that an ostomy device should have a double female ring structure which can interengage with a male ring. The male ring may be on the bag and the female ring on a skin-attachable adhesive pad, or vice-versa. The outer ring on the female ring is circular and flexible and has a pair of inwardly-extending catches at opposite ends of a diameter. By pressing on two diametrically extending lugs, whose diameter is substantially at right angles to the diameter joining the catches, the outer female ring is deformed so that the catches are caused to move radially outwardly, so permitting separation of the two coupling parts.
This arrangement, though perhaps operable in theory, has serious disadvantages in practice, for example (i) to connect or disconnect it is necessary to hold the coupling at four places, approximately spaced at 90.degree. intervals around the periphery, (ii) pressing on two diametrically opposed regions will tend to bend the coupling out of its normal plane and the forces applied may easily cause the body side pad to be partially (or wholly) detached from the skin of the wearer, also the need to press in both ends of the diameter fully, and simultaneously, means that releasing the bag side coupling is subject to uncertainty, (iii) the repeated attachment and withdrawal of the bag side coupling part will cause the o-ring (provided to prevent escape of excreted matter between the male and female rings) to become worn, so compromising its sealing qualities with potentially highly embarrassing and undesirable results, (iv) the wearer may find it difficult to determine whether or not the two coupling parts are accurately arranged, (v) the accuracy and forces needed for manipulation to connect or disconnect will be well beyond the capability of an infirm, confused, elderly or impatient wearer; (vi) it is hard to be sure that the appliance is properly locked; and (vii) in the case of large sizes, the old and infirm will find it physically difficult to span with their hand and push in diametrally opposed regions of the ring. A further disadvantage of Kubo and of many present day ostomy couplings is that they extend outwardly from the body an undesirable distance, and so cause bulges or bumps under the wearer's clothing.
It is an aim of this invention to provide an improved design.